Pharmaceutical formulations comprising nitrocatechol derivatives and methods of making thereof

ABSTRACT

The present disclosure relates to compositions and pharmaceutical formulations comprising at least one active pharmaceutical ingredient chosen from nitrocatechol derivatives of formula I as defined herein and salts, esters, hydrates, solvates and derivatives thereof and methods of making said compositions and pharmaceutical formulations.

This is a continuation of application Ser. No. 12/750,956, filed Mar.31, 2010, and claims the benefit of U.S. Provisional Application No.61/165,778, filed Apr. 1, 2009, which is incorporated herein byreference.

FIELD OF THE DISCLOSURE

The present disclosure relates to compositions and pharmaceuticalformulations comprising at least one active pharmaceutical ingredientchosen from nitrocatechol derivatives and salts thereof.

BACKGROUND

Levodopa (L-DOPA) has been used in clinical practice for several decadesin the symptomatic treatment of various conditions, includingParkinson's disease. L-DOPA is able to cross the blood-brain barrier,where it is then converted to dopamine and increases the levels thereof.However, conversion of L-DOPA to dopamine may also occur in theperipheral tissue, possibly causing adverse effects upon administrationof L-DOPA. Therefore, it has become standard clinical practice toco-administer a peripheral amino acid decarboxylase (AADC) inhibitor,such as carbidopa or benserazide, which prevents conversion to dopaminein peripheral tissue.

This has led to an interest in the development of inhibitors of theenzyme catechol-O-methyltransferase (COMT) based on the hypothesis thatinhibition of the enzyme may provide clinical improvements in patientsafflicted with Parkinson's disease undergoing treatment with L-DOPA,since COMT catalyses the degradation of L-DOPA.

It has been found, as set forth in International Publication Nos. WO2007/013830 and WO 2007/117165, which are incorporated herein byreference, that compounds of formula I disclosed herein, which arenitrocatechol derivatives, are potent and long-acting COMT inhibitors.Those compounds are both bioactive and bioavailable. Thus, compounds offormula I have potentially valuable pharmaceutical properties in thetreatment of some central and peripheral nervous system disorders whereinhibition of O-methylation of catecholamines may be of therapeuticbenefit, such as, for example, mood disorders; movement disorders, suchas Parkinson's disease, parkinsonian disorders and restless legssyndrome; gastrointestinal disturbances; edema formation states; andhypertension. Furthermore, these compounds may also have activity intreating other diseases and disorders, not related to the inhibition ofO-methylation of catecholamines.

It has also been found, however, that the compounds of formula I mayexhibit a low bulk density, poor solubility and/or poor flowcharacteristics, which increases the difficulty in formulating and/ormanufacturing a dosage formulation containing the active compound.

The inventors have now discovered compositions and formulations thereofcomprising at least one active pharmaceutical ingredient (“API”) chosenfrom nitrocatechol derivatives of formula I as defined herein and salts,esters, hydrates, solvates and other derivatives thereof. In variousembodiments, the at least one nitrocatechol derivative is2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide or5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diol.The at least one nitrocatechol derivative may also be a mixture of2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide and5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diol.In at least one embodiment, the API may be present in granular form. Insome embodiments, the compositions and/or formulations may comprise afurther API, for example the compositions and/or formulations maycomprise, in addition to the at least one API chosen from nitrocatecholderivatives of formula I, further APIs such as L-DOPA, a peripheralamino acid decarboxylase (AADC) inhibitor, such as carbidopa orbenserazide.

In further embodiments, the compositions and/or formulations may alsocomprise at least one phosphate derivative and at least onepolyvinylpyrrolidone (PVP) derivative compound. In various exemplaryembodiments when the API is granular, the at least one phosphatederivative and at least one PVP derivative compound may, independently,be intragranular (i.e., granulated with the API and/or contained withinthe same granules as the API), extragranular (i.e., present outside thegranules of API), or part intragranular and part extragranular. In yetfurther embodiments of the present disclosure, the compositions mayexhibit a bulk density that is greater than that of the API alone, andthat may, in certain embodiments, be significantly increased. In yetfurther embodiments, the compositions may exhibit good flowability, thatmay, in certain embodiments, be significantly improved over that of theAPI alone. The compositions may also exhibit improvements in othercharacteristics such as compressibility and content uniformity (i.e.,the API is homogenously distributed throughout the composition, forexample throughout the granule). Use of the methods described herein mayalso result in improvements in the granule properties of thecompositions such as improved granule size and uniformity of granulesize and/or of granule mass.

SUMMARY

In accordance with the detailed description and various exemplaryembodiments described herein, the present disclosure relates tocompositions and formulations thereof comprising at least one API chosenfrom nitrocatechol derivatives of formula I as defined herein and salts,esters, hydrates, solvates and other derivatives thereof thereof. Invarious exemplary embodiments, the at least one nitrocatechol derivativemay be2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide or5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diol.The at least one nitrocatechol derivative may also be a mixture of2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide and5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diol.In at least one embodiment, the API may be present in granular form. Insome embodiments, the compositions and/or formulations may comprise afurther API, for example the compositions and/or formulations maycomprise, in addition to the at least one API chosen from nitrocatecholderivatives of formula I, further APIs such as L-DOPA, a peripheralamino acid decarboxylase (AADC) inhibitor, such as carbidopa orbenserazide.

In further embodiments, the compositions and/or formulations may alsocomprise at least one phosphate derivative and at least one PVPderivative compound. In various exemplary embodiments when the API isgranular, the at least one phosphate derivative and the at least one PVPderivative compound may, independently, be intragranular, extragranular,or part intragranular and part extragranular. In yet further embodimentsof the present disclosure, the compositions may exhibit a bulk densitythat is greater than that of the API alone, and that may, in certainembodiments, be significantly increased. In yet further embodiments, thecompositions may exhibit good flowability, that may, in certainembodiments, be significantly improved over that of the API alone.

The compositions may also exhibit improvements in other characteristicssuch as compressibility and content uniformity (i.e., the API ishomogenously distributed throughout the composition, for examplethroughout the granule). Use of the methods described herein may alsoresult in improvements in the granule properties of the compositionssuch as improved granule size and uniformity of granule size and/or ofgranule mass.

DETAILED DESCRIPTION

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory only,and are not restrictive of the invention as claimed. Other embodimentsof the disclosure will be apparent to those skilled in the art fromconsideration of the specification and practice of the inventiondisclosed herein.

In various exemplary embodiments, the present disclosure relates tocompositions and formulations thereof comprising at least one API chosenfrom nitrocatechol derivatives of formula I as defined herein and salts,esters, hydrates, solvates and other derivatives thereof, at least onephosphate derivative, and at least one PVP derivative compound. In atleast one embodiment, the API may be present in granular form.

As used herein, the terms “granules,” “granular form,” “API granules”and variations thereof, are intended to include the particles producedby wet or dry granulation of the API chosen from nitrocatecholderivatives of formula I as defined herein and salts, esters, hydrates,solvates and other derivatives thereof. In various embodiments of thepresent disclosure, the granules may further comprise at least onephosphate derivative and/or at least one PVP derivative compound.

As used herein, the term “composition,” and variations thereof, isintended to mean a composite comprising the at least one API, at leastone phosphate derivative, and at least one PVP derivative compound. Incertain embodiments, the composition may comprise two or morenitrocatechol derivatives of formula I (i.e. APIs), for example thecomposition may comprise2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide and5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diol,at least one phosphate derivative, and at least one PVP derivativecompound. In at least one embodiment, the composition may comprisegranules of the at least one API, and the at least one phosphatederivative and the at least one PVP derivative compound may, in variousembodiments, be independently intragranular (i.e., granulated with theAPI and/or contained within the same granules as the API), extragranular(i.e., present outside the granules of API), or part intragranular andpart extragranular. For example, the phosphate derivative may be 10 wt %to 90 wt %, 20 wt % to 80 wt %, 30 wt % to 70 wt %, 40 wt % to 60 wt %,or about 50 wt % intragranular, with the remaining portion beingextragranular. The PVP derivative may be 10 wt % to 90 wt %, 20 wt % to80 wt %, 30 wt % to 70 wt %, 40 wt % to 60 wt %, or about 50 wt %intragranular, with the remaining portion being extragranular. Invarious exemplary embodiments, the composition may comprise at least oneexcipient, and in a further embodiment, the composition may beappropriate for filling a capsule and/or making a tablet, and/ordirectly administering to patients, for examples packaged as sachets.

As used herein, the terms “formulation,” “pharmaceutical formulation,”and variations thereof, are intended to include compositions describedherein that are further processed or formulated into a dosage form. Byway of example only, in various exemplary embodiments, the formulationsmay comprise a composition described herein, typically in the form ofgranules, in a dosage form suitable for administration to a subject,such as a capsule or a compressed form such as a tablet. In a furtherexemplary embodiment, the formulations may comprise a compositiondescribed herein, typically in the form of granules, mixed with at leastone excipient in a dosage form suitable for administration to a subject,such as a capsule or a compressed form such as a tablet.

As used herein, the nitrocatechol derivatives of formula I are definedas follows:

wherein:

-   R₁ and R₂ are independently selected from hydrogen or a group which    is hydrolysable under physiological conditions, optionally    substituted lower alkanoyl or aroyl;-   X is a methylene group;-   Y is an atom of oxygen, nitrogen, or sulphur,-   n is selected from 0, 1, 2, and 3;-   m is 0 or 1;-   R₃ is a pyridine group chosen from the formulas A, B, C, D, E and F    which is connected as indicated by the unmarked bond:

-   -   wherein:    -   R₄, R₅, R₆, and R₇ are independently chosen from hydrogen,        C₁-C₆-alkyl, C₁-C₆-thioalkyl, C₁-C₆-alkoxy, C₆-C₁₂-aryloxy or a        C₆-C₁₂-thioaryl group, C₁-C₆-alkanoyl or C₇-C₁₃-aroyl group,        amino, C₁-C₆-alkylamino, C₁-C₆-dialkylamino,        C₃-C₁₂-cycloalkylamino, C₃-C₁₂-heterocycloalkylamino,        C₁-C₆-alkylsulphonyl, C₆-C₁₂-arylsulphonyl, halogen,        C₁-C₆-haloalkyl, e.g., trifluoromethyl, cyano, nitro or a        heteroaryl group; or two or more of residues R₄, R₅, R₆ and R₇        taken together represent aliphatic or heteroaliphatic rings or        aromatic or heteroaromatic rings; and

-   P is a central unit, for example a planar unit, such as those    selected from the regioisomers of 1,3,4-oxadiazol-2,5-diyl;    1,2,4-oxadiazol-3,5-diyl, 4-methyl-4H-1,2,4-triazol-3,5-diyl;    1,3,5-triazin-2,4-diyl; 1,2,4-triazin-3,5-diyl;    2H-tetrazol-2,5-diyl; 1,2,3-thiadiazol-4,5-diyl;    1-alkyl-3-(alkoxycarbonyl)-1H-pyrrol-2,5-diyl wherein alkyl is    represented by methyl, ethyl, n-propyl and n-butyl and wherein    alkoxy is represented by methoxy, ethoxy, n-propoxy and isopropoxy;    1-alkyl-1H-pyrrol-2,5-diyl wherein alkyl is represented by methyl,    ethyl, n-propyl and n-butyl; thiazol-2,4-diyl; 1-H-pyrazol-1,5-diyl;    pyrimidin-2,4-diyl; oxazol-2,4-diyl; carbonyl; 1H-imidazol-1,5-diyl;    isoxazol-3,5-diyl; furan-2,4-diyl; 3-alkoxycarbonylfuran-2,4-diyl    wherein alkoxy is represented by methoxy, ethoxy, n-propoxy, and    isopropoxy; benzene-1,3-diyl; and (Z)-1-cyanoethen-1,2-diyl.    Suitable groups which are hydrolysable under physiological    conditions are well known in the art and include groups that form,    with the 0 atom, an ether, ester, or carbonic acid ester linkage.

In one exemplary embodiment, P is chosen from 1,3,4-oxadiazol-2,5-diyland 1,2,4-oxadiazol-3,5-diyl.

In a further exemplary embodiment, the at least one nitrocatecholderivative of formula I is2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide or5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diol.The at least one nitrocatechol derivative of formula I may also be amixture of2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide and5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diol.In embodiments where the at least one nitrocatechol derivative offormula I is a mixture of two nitrocatechol derivatives, such as2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide and5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diol,the ratio of the two components may be approximately 50:50 or anyvariation thereof, such as approximately 60:40, 70:30, 80:20, 90:10,95:5, 97:3, or 99:1, or the proportion of one of the nitrocatecholderivatives may be present in an amount up to and including 5%, up to anincluding 3% or up to and including 1% of the amount of the othernitrocatechol, for example5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diolmay be present in an amount of up to and including 5%, up to andincluding 3% or up to and including 1% of the amount of2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide.

The at least one API chosen from nitrocatechol derivatives of formula Iand salts, esters, hydrates, solvates and other derivatives thereof asdisclosed herein may exhibit low bulk density, thereby making itdifficult to formulate and manufacture a dosage form. For example,2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide may exhibit a bulk density of less than 0.1 g/ml prior togranulation and/or formulation, and5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diolmay exhibit a bulk density of around 0.2 g/ml prior to granulationand/or formulation, and as determined by the method describedhereinbelow.

Formulating APIs of low bulk density can often give rise to manyproblems, for example poor content uniformity, particle segregation,little or no flowability, high average weight variability, cappingand/or lamination of tablets, and high tablet friability.

In at least one exemplary embodiment, the amount (or dosage) of the atleast one API present in the compositions and/or formulations of thepresent disclosure may be a therapeutically effective amount. As usedherein, “therapeutically effective amount” means an amount of atherapeutic agent sufficient to treat, alleviate, and/or prevent anycondition treatable and/or preventable by administration of acomposition of the disclosure, in any degree. That amount can, forexample, be an amount sufficient to exhibit a detectable therapeutic orpreventative or ameliorative effect. The effect may include, forexample, treatment, alleviation, and/or prevention of the conditionslisted herein. The actual amount required, e.g. for treatment of anyparticular patient, will depend upon a variety of factors including thedisorder being treated and/or prevented; its severity; the specificpharmaceutical composition employed; the age, body weight, generalhealth, gender, and diet of the patient; the mode of administration; thetime of administration; the route of administration; the rate ofexcretion of the therapeutic agent; the duration of the treatment; anydrugs used in combination or coincidental with the therapeutic agent;and other such factors well known to those skilled in the art. Invarious embodiments, for example, a formulation, i.e, a capsule ortablet dosage form, may contain 1 mg or more of API, for example 2.5 mgor more, 5 mg or more, 10 mg or more, 20 mg or more, 40 mg or more, 50mg or more, or 100 mg or more of API. The API content in the compositionand/or formulation can therefore vary from 0.02 wt % to 90 wt % forexample 0.1 wt % to 70 wt, 0.2 wt % to 50 wt % or 0.3 wt % to 45 wt %.

The at least one phosphate derivative of the present disclosure is anysubstance comprising calcium phosphate, including, but not limited to:calcium phosphate, dibasic anhydrous (for example, A-TAB™, Di-Cafos™A-N, Emcompress™ Anhydrous, and Fujicalin™); calcium phosphate, dibasicdihydrate (for example, Cafos™, Calipharm™, Calstar™, Di-Cafos™,Emcompress™); and calcium phosphate tribasic (for example, Tri-Cafos™,TRI-CAL™ WG, TRI-TAB™).

In various embodiments, the amount of at least one phosphate derivativepresent in a composition and/or formulation of the present disclosuremay constitute 0.5 wt % to 99.5 wt % of the composition and/orformulation, for example, 10 wt % to 80 wt %, 20 wt % to 60 wt %, or 25wt % to 40 wt %, such as for example 35 wt %, of the total weight of thecomposition and/or formulation. The at least one phosphate derivativemay be intragranular, extragranular, or part intragranular and partextragranular. The amount of the at least one phosphate derivative mayvary depending, in part, upon the desired dosage and bulk density.

The at least one PVP derivative compound of the present disclosure isany substance comprising polyvinylpyrrolidone or a substituted versionthereof, including, but not limited to: povidone (for example, Plasdone™and Kollidon™); copovidone (for example, plasdone S-630™ and kollidonVA-64™); and cross-linked PVP (known also as crospovidone).

In various embodiments, the amount of at least one PVP derivativecompound present in a composition and/or formulation of the presentdisclosure may constitute 0.1 wt % to 40 wt % of the composition and/orformulation, for example, 1 wt % to 30 wt %, 2 wt % to 20 wt %, 3 wt %to 10 wt %, or 6 wt % to 8 wt %, such as, for example 7 wt %, of thetotal weight of the composition and/or formulation. The PVP derivativecompound may be intragranular, extragranular or part intragranular andpart extragranular. The amount of the at least one PVP derivativecompound may vary depending, in part, upon the desired dosage and bulkdensity.

The invention also relates to a method of making a composition orformulation of the inventions comprising the steps of:

-   -   granulating at least one active pharmaceutical ingredient chosen        from nitrocatechol derivatives of formula I and salts, esters,        hydrates, solvates and other derivatives thereof to form        granules;    -   mixing at least one phosphate derivative with the at least one        active pharmaceutical ingredient before, during or after        granulation; and    -   mixing at least one polyvinylpyrrolidone derivative compound        with the at least one active pharmaceutical ingredient before,        during or after granulation.

In various exemplary embodiments of the present disclosure, the at leastone API, at least one phosphate-derivative, and at least one PVPderivative compound are combined by mixing (also referred to herein asblending). The appropriate apparatus and mixing time and rate may bedetermined by those of skill in the art based on, for example, theamount of material present, the type of mixing process used, and otherparameters known to those of skill in the art. For example, in variousembodiments, the components may be mixed manually, using a V-blender, ahigh shear mixer, or any other mixing apparatus and/or process known tothose of skill in the art. As a further example, in various embodiments,the components may be mixed for any appropriate period of time, such as1 to 30 minutes or 2 to 10 minutes.

In various exemplary embodiments, granules may be formed by dry or wetgranulation. In at least one embodiment, the granules are wet-granulatedusing at least one granulation liquid. By way of example, the at leastone granulation liquid may be chosen from water, ethanol, isopropanol,and/or acetone. In at least one embodiment, the granulation liquid iswater. The appropriate apparatus and mixing time and rate forgranulation may be determined by those of skill in the art based on, forexample, the amount of material and the amount of granulation liquid, ifpresent. For example, in various embodiments, the components may begranulated manually, using a high shear mixer, planetary mixer or anyother granulator apparatus and/or process known to those of skill in theart. As a further example, in various embodiments, the components may begranulated for any appropriate period of time, such as 1 to 60 minutesor 2 to 30 minutes. Determination of the endpoint of granulation iswithin the capability of the skilled person but can be determined byobservance of stabilization of granule size and particle cohesionresulting in a decrease in air trapped inside the granule, or byattainment of steady state of rheological or correlated determination ofvoltage, conductivity torque, power consumption or near IR techniques.As a further example, granulation speeds may vary from 5 to 100% of thegranulator mixing speed, such as from 25 to 100%.

In at least one exemplary embodiment, after the wet-granulation processis complete, the granules may then be dried. Granules should be dried toloss on drying (LOD) values below 6%, preferably below 5%, morepreferably between 1-3%. A suitable technique for determining LOD valuesis as described in USP 31, vol. 1, test <731>, The United StatesPharmacopeia Convention, 2008. The test involves accurately weighing thesubstance to be tested (m₀), (e.g. using a sample amount of 1 to 10 g).The test specimen is then dried at 105° C. until a constant weight(m_(f)) is achieved. The moisture can be calculated by using thefollowing expression:LOD (%)=[(m _(o) −m _(f))]*100

The appropriate drying apparatus and drying time and temperature may bedetermined by those of skill in the art based on, for example, theamount of material present, moisture content of the material, and thegranulation liquid. As non-limiting examples, a fluid bed dryer or traydryer may be used, for example at a temperature of 25° C. or higher, 40°C. or higher, or 70° C. or higher, to dry the granules. For example, thegranules may be dried at a temperature of 66° C.

In various exemplary embodiments, the granules may be sieved. Sievingthe granules may originate granules of homogeneous particle size, andmay, for example, be used to select particles of an advantageous sizefor formulating or manufacturing a dosage form. In various embodiments,the granules may be sieved over a screen of 0.5 mm or larger, forexample a 0.6 mm, 0.8 mm, 1.0 mm and 1.6 mm screen.

In various exemplary embodiments, the composition may include at leastone excipient which may be blended with the at least one API, at leastone phosphate derivative, and at least one PVP derivative compound. Inone embodiment, the at least one excipient is blended with the APIgranules. The at least one excipient may be chosen from, but is notlimited to, conventional excipients such as a) fillers, diluents orextenders, such as, for example, calcium carbonate, fructose or kaolin;b) binders such as, for example, acacia, sucrose and zein; c)disintegrants such as, for example, agar and calcium carbonate; d)lubricants such as, for example, calcium stearate, glycerinemonostearate, glyceryl behenate, glyceryl palmitostearate, hydrogenatedcastor oil, hydrogenated vegetable oil type I, magnesium laurylsulphate, magnesium stearate, medium-chain triglycerides, poloxamer,polyethylene glycol, sodium benzoate, sodium chloride, sodium laurylsulphate, sodium stearyl fumarate, stearic acid, talc, sucrose stearate,and zinc stearate; and e) glidants such as, for example, tribasiccalcium phosphate, calcium silicate, cellulose, powdered, colloidalsilicon dioxide, magnesium silicate, magnesium trisilicate, starch, andtalc. In further embodiments, the composition and/or formulation doesnot comprise any such additional excipients.

In various exemplary embodiments, the at least one excipient may beadded before or during granulation of the at least one API and, thus,may be present as an intragranular excipient. In other exemplaryembodiments, the at least one excipient may be added to the formulationafter granulation, for example by blending with the granules, and thusmay be present as an extragranular excipient. In various exemplaryembodiments, at least one first excipient may be added prior to orduring granulation and at least one second excipient and/or more of theat least one first excipient may be added to the composition aftergranulation. For example, in various embodiments, fillers, binders anddisintegrants can be added prior to or during granulation, whereasflowability agents and glidants can be added after granulation.

In some exemplary embodiments, the composition and/or formulationcomprise the following:

API 0.2-50.0 wt % Phosphate derivate 5.0-50.0 wt % Additional Filler0.0-85.0 wt % Povidone derivate 1.0-15.0 wt % Lubricants 1.0-15.0 wt %Disintegrants 1.0-15.0 wt % API 0.2-30.0 wt % Phosphate derivate20.0-50.0 wt % Additional Filler 0.0-85.0 wt % Povidone derivate3.0-10.0 wt % Lubricants 1.0-10.0 wt % Disintegrants 3.0-10.0 wt % API20.0-50.0 wt % Phosphate derivate 20.0-50.0 wt % Additional Filler0.0-55.0 wt % Povidone derivate 3.0-10.0 wt % Lubricants 1.0-10.0 wt %Disintegrants 3.0-10.0 wt %

In various exemplary embodiments, the composition comprising granules ofthe at least one API, the at least one phosphate derivative, and the atleast one PVP derivative compound may be used to make a formulation,such as, for example, may be used to fill capsules or may be compressedto form tablets.

Capsules for use in the present disclosure include, but are not limitedto, gelatin capsules and hydroxypropylmethyl cellulose (hypromellose)capsules. Suitable methods for filling such capsules with a compositionaccording to an embodiment of the disclosure are well-known to those ofskill in the art.

Tablets of the present disclosure may be formed by any method known tothose of skill in the art such as compression. In at least oneembodiment of the present disclosure, tablets may be coated, for examplewith aqueous based film-coatings, solvent based film-coatings and/orsugar coatings.

The formulations of the invention may also be colored, for example byinclusion of a coloring in the composition of the invention, or bycoating the composition or formulation.

In various exemplary embodiments of the present disclosure, thecompositions may exhibit improved bulk density and/or flow propertiesrelative to those of the API alone. As used herein, the terms “improvedbulk density,” “significantly improved bulk density,” and variationsthereof mean that the bulk density of the composition is approximatelyat least double, at least three times, at least four times or at leastfive times that of the API alone. It is within the ability of one ofskill in the art to determine the bulk density of a compound orcomposition using methods generally accepted in the art. However,suitable methods include, for example, the European Pharmacopeia edition6, Test 2.9.15 “apparent volume,” pages 285-286, EDQM, 2007, and USP 31,vol. 1 test <616> page 231-232, The United States PharmacopeiaConvention, 2008. An example of a suitable method is described below:

Apparatus:

-   -   settling apparatus capable of producing in 1 minute 250±15 taps        from a height of 3±0.2 mm. The support for the graduated        cylinder with its holder, has a mass of 450±5 g    -   a 250 ml graduated cylinder (2 ml intervals) with a mass of        220±40 g

Method: Into a dry cylinder, introduce without compacting, 100.0 g (m g)of the test substance. Secure the cylinder in its holder. Read theunsettled apparent volume (V₀) to the nearest milliliter. Carry out 10,500 and 1250 taps and read the corresponding volumes V₁₀, V₅₀₀, V₁₂₅₀,to the nearest milliliter. If the difference between V₅₀₀ and V₁₂₅₀ isgreater than 2 ml, carry out another 1250 taps.

Alternatively, if it is not possible to select 100.0 g, select a testsample of any mass but with a volume between 50 ml and 250 ml, measureits apparent volume, V₀ as described above, and weigh the sample andspecify the mass in the expression of results. Bulk/apparent density maythen be determined in g/ml using the following formula:m/V ₀where m is the mass in grams and V₀ the unsettled apparent volume.

Tapped apparent density may then be determined in g/ml using thefollowing formula:M/V ₁₂₅₀where m is the mass in grams and V₁₂₅₀ the apparent volume after 1250hubs.

For example, as set forth above,2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide, a nitrocatechol of formula I, may exhibit a bulk density ofless than 0.1 g/ml prior to granulating. Compositions according to thepresent disclosure comprising granules of2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide may exhibit bulk densities of 0.2 g/ml or greater, for example0.4 g/ml or greater, or 0.5 g/ml or greater, or 0.6 g/ml or greater. Inat least one embodiment of the disclosure, compositions of the presentdisclosure for use as final blends for capsule filling or tablettingcomprising2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide may also exhibit bulk densities or apparent bulk densities of0.2 g/ml or greater, for example 0.4 g/ml or greater, 0.5 g/ml orgreater, or 0.6 g/ml or greater.

In at least one embodiment of the disclosure, compressed formulations ofthe disclosure such as tablets exhibit apparent density of 0.5 g/mL to1.5 g/mL, such as 0.6 g/mL to 1.4 g/mL, 0.7 g/mL to 1.3 g/mL, or 0.8g/mL to 1.2 g/mL.

The apparent density of a compressed formulation is measured in terms ofmass and volume of the formulation and is well within the capabilitiesof the skilled person.

It is within the ability of one of skill in the art to determine thecompressibility of a compound or composition using methods generallyaccepted in the art. However, suitable methods include but are notlimited to, using USP 31, vol. 1, test <1174>, The United StatesPharmacopeia Convention, 2008, and measuring both the bulk volume (V₀)and the tapped volume (V_(f)) of the granules. The compressibility index(CI) may then be calculated using the following formula:CI (%)=100×[(V ₀ −V _(f))/V ₀]

It is within the ability of one of skill in the art to determine theflowability of a compound or composition using methods generallyaccepted in the art. However, suitable methods include but are notlimited to, testing the flow rate through an orifice described in USP31, vol. 1, test <1174>, The United States Pharmacopeia Convention,2008, in which case, the flowability may be measured as the mass pertime flowing through the 10 mm diameter opening of a glass funnel.

Unless otherwise indicated, all numbers used in the specification andclaims are to be understood as being modified in all instances by theterm “about,” whether or not so stated. It should also be understoodthat the precise numerical values used in the specification and claimsform additional embodiments of the disclosure. Efforts have been made toensure the accuracy of the numerical values disclosed in the Examples.Any measured numerical value, however, can inherently contain certainerrors resulting from the standard deviation found in its respectivemeasuring technique.

As used herein the use of “the,” “a,” or “an” means “at least one,” andshould not be limited to “only one” unless explicitly indicated to thecontrary. Thus, for example, the use of “the formulation” or “aformulation” is intended to mean at least one formulation.

Other embodiments of the disclosure will be apparent to those skilled inthe art from consideration of the specification and practice of thepresent disclosure. It is intended that the specification and examplesbe considered as exemplary only, with a true scope and spirit of theinvention being indicated by the claims.

EXAMPLES

The following examples are not intended to be limiting of the inventionas claimed.

Example 1

Four laboratory scale high dosage capsules were made by first mixing theAPI and dicalcium phosphate and/or microcrystalline cellulose,croscarmellose-sodium, and/or povidone, and/or pregelatinized starch inthe amounts set forth in Table 1 below in a laboratory scale high shearmixer (Stephan). The API used in these examples was2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide. Purified water was added to each mixture, and the mixtures weregranulated.

The granules were then dried in a laboratory scale fluid bed dryer(Aeromat). The dried granules were sieved and then blended with theremaining ingredients set forth in Table 1 in a 1 L tumble mixer(Turbula). Capsules were filled with the composition using a manualfilling machine.

The granules and final compositions were evaluated for bulk and tappeddensity using the methods described above. Flowability was also accessedby testing the flow rate through an orifice described in USP 31, vol. 1,test <1174>, The United States Pharmacopeia Convention, 2008. Theflowability was measured as the mass per time flowing through the 10 mmdiameter opening of a glass funnel.

TABLE 1 Batch Ingredient (%) A B C D API 35.1 35.1 35.1 35.1Di-Calcium-Phosphate 33.3 33.3 Microcrystalline Cellulose 12.3 12.3 31.6(Avicel PH 102) Microcrystalline Cellulose 45.6 (Avicel PH 101)Croscarmellose-Sodium 1.8 Povidone 7.0 7.0 Starch Pregelatinized 8.8 8.8Purified Water q.s. q.s. q.s. q.s. Microcrystalline Cellulose 15.8(Avicel PH 102) Croscarmellose-Sodium 3.5 3.5 3.5 3.5 Silica ColloidalHydrate 3.5 3.5 3.5 3.5 Talc 1.8 1.8 1.8 1.8 Magnesium-Stearate 1.8 1.81.8 1.8 Bulk density granules [g/mL] 0.425 0.365 0.323 0.236 Tappeddensity of granules [g/mL] after  10 hubs 0.462 0.388 0.359 0.248 1250hubs 0.556 0.487 0.414 0.337 Flowability granules +++ ++− ++− −−− Bulkdensity final 0.485 0.395 0.360 0.240 composition [g/mL] Tapped densityfinal composition [g/L] after  10 hubs 0.527 0.416 0.387 0.247 1250 hubs0.614 0.506 0.462 0.320 Flowability final composition +++ ++− ++− +−−Flowability: “+++” = very good; “−−−” = not flowable

As can be seen from Table 1, although the presence of povidone ordicalcium phosphate improved bulk density and flowability properties(see Batches B and C) when compared to neither being present (see BatchD), the improvement in bulk density was significantly greater when bothof these excipients were present (see Batch A). Similar flowability datawere obtained for granules and final mixture, with the granules andfinal mixture of Batch A exhibiting very good flowability.

Example 2

To prepare low dosage capsules, two variations of the Batch Aformulation were prepared at the laboratory scale. The two batches oflow dosage capsules were made using the compositions set forth in Table2 below. First the API, dicalcium phosphate, microcrystalline cellulose,croscarmellose-sodium, and povidone in the amounts set forth in Table 3below were mixed in a V-blender. The API used in these examples was2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide. Purified water was added to the mixture, and the mixture wasmixed manually and granulated.

The granules were then dried in a tray dryer at 50° C. for about 300minutes. The dried granules were sieved. The sieved granules were thenblended with the remaining croscarmellose-sodium and silica colloidalhydrate set forth in Table 3 in a V-blender. Then the magnesium stearateand talc were added and mixed. Capsules were filled with the compositionusing a capsule filling machine.

The granules and final compositions were evaluated for bulk and tappeddensity and flowability using the methods described in Example 1 above.The compressibility index was assessed using USP 31, vol. 1, test<1174>, The United States Pharmacopeia Convention, 2008, and measuringboth the bulk volume (V₀) and the tapped volume (V_(f)) of the granules.The compressibility index (CI) was then calculated using the followingformula:CI (%)=100×[(V ₀ −V _(f))/V ₀]The results are set forth in Table 2 below.

TABLE 2 Batch Ingredient (%) E F API 1.8 1.8 Di-Calcium-Phosphate,di-hydrated 33.3 57.9 (Ecompress) Microcrystalline Cellulose 45.6 21.0(Avicel PH 102) Croscarmellose-Sodium 1.8 1.8 Povidone 7.0 7.0 PurifiedWater q.s. q.s. Croscarmellose-Sodium 3.5 3.5 Silica Colloidal Hydrate3.5 3.5 Talc 1.8 1.8 Magnesium-Stearate 1.8 1.8 Bulk density of granules[g/ml] 0.53 0.63 Tapped density of granules 0.63 0.74 [g/ml] after 1250hubs Compressibility index (%) 6.0 5.5 Flow rate (g/sec) 17.6 19.4

As seen in Table 2 above, the bulk density of the granules of Batch Fwas much higher than that of the high dosage formulations previouslystudied; therefore, it was not possible to fill capsules with granulesfrom batch F with adequate mass. Batch E, however, gave rise to granulesand capsules with similar properties to those of the high dosageformulations of Example 1. Batch E also presented good flow andcompressibility properties.

Example 3

Three batches of pilot scale capsules of varying dosages were made usingthe compositions set forth in Table 3 below. Batch H is low dosagecapsules, Batch J is intermediate dosage capsules, and Batch L is highdosage capsules.

First the API, dicalcium phosphate, microcrystalline cellulose,croscarmellose-sodium, and povidone in the amounts set forth in Table 3below were mixed in a high-shear mixer granulator. The API used in theseexamples was2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide. Purified water was added to the mixture, and the mixture wasmixed in a high-shear mixer granulator.

The granules were then dried in a fluid bed dryer. The dried granuleswere sieved. The sieved granules were then blended with the remainingcroscarmellose-sodium and silica colloidal hydrate set forth in Table 3in a V-blender. Then the magnesium stearate and talc were added andmixed. Capsules were filled with the compositions using a capsulefilling machine.

Additionally, two laboratory scale batches were made, Batch G (lowdosage) and K (high dosage), by the method set forth in Example 2. Thecompositions of these batches are set forth in Table 3 below.

The granules, compositions, and capsules were evaluated in the samemanner set forth in Example 2, and the results are set forth in Table 3below. Additionally, uniformity of mass was assessed by the individualweight of 20 capsules and average mass and standard deviation werecalculated. These results are also set forth in Table 3.

TABLE 3 Batch Ingredient (%) G H J K L API 1.8 1.8 8.8 35.1 35.1Di-Calcium-Phosphate 33.3 33.3 33.3 33.3 33.3 (Emcompress)Microcrystalline Cellulose 45.6 45.6 38.6 12.3 12.3 (Avicel PH 102)Croscarmellose-Sodium 1.8 1.8 1.8 1.8 1.8 Povidone 7.0 7.0 7.0 7.0 7.0Purified Water q.s. q.s. q.s. q.s. q.s. Croscarmellose-Sodium 3.5 3.53.5 3.5 3.5 Silica Colloidal Hydrate 3.5 3.5 3.5 3.5 3.5 Talc 1.8 1.81.8 1.8 1.8 Magnesium-Stearate 1.8 1.8 1.8 1.8 1.8 Bulk density ofgranules 0.53 0.88 0.82 0.36 0.76 [g/ml] Tapped density of granules 0.630.91 0.87 0.43 0.83 [g/ml after 1250 hubs] Compressibility index (%) 6.05.4 6.7 10.5 6.2 Flow rate (g/sec) 17.6 23.5 24.6 18 23.4 Uniformitymass (RSD %) of 4.2 2.4 2.6 5.3 2.9 size 0 capsules

The results set forth in Table 3 above show that most of the propertiesof the pilot scale batches were improved upon scale-up of the process(i.e., as compared to the batches set forth in Examples 1-2 above).Moreover, the bulk density, tapped density, and flow rate, inparticular, indicate achievement of a final product with propertiessurprisingly superior to that of the API. The API used in the batches ofthe present example and the others set forth herein possesses a very lowbulk density (<0.1 g/ml) and no flow; whereas, the granules of some ofthe present batches exhibit bulk densities higher than 0.8 g/ml (anincrease of over 800%) and a flow rate higher than 20 g/s. Even at highAPI doses (e.g., around 35%) the bulk density was greatly improved: fromless than 0.1 g/ml to 0.76 g/ml.

Comparative Example 1

Five high dosage capsules were made by first mixing the API, the firstmicrocrystalline cellulose amount, the first ethylcellulose amount andthe maize starch in the amounts set forth in Table 4 in a high shearmixer. The API used in these examples was2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide. Purified water was added to each mixture, and the mixtures weregranulated.

The granules were then dried in a fluid bed dryer (Aeromat). The driedgranules were sieved and then blended with the remaining ingredients setforth in Table 4 in a 1 L tumble mixer (Turbula). Capsules were filledwith the composition using a manual filling machine.

TABLE 4 Batch: Ingredient (%) CA CB CC CD CE API 35.1 35.1 35.1 35.135.1 Microcrystalline 17.5 17.5 15.8 Cellulose Ethylcellulose 1.8 1.81.8 Maize Starch 8.8 8.8 8.8 8.8 8.8 Purified Water q.s. q.s q.s q.s.q.s. Microcrystalline 28.1 43.9 14.0 Cellulose Ethylcellulose 28.1 43.914.0 Croscarmellose-Sodium 3.5 3.5 3.5 3.5 3.5 Silica Colloidal Hydrate3.5 3.5 3.5 3.5 3.5 Talc 1.8 1.8 1.8 1.8 1.8 Magnesium-Stearate 1.8 1.81.8 1.8 1.8 Bulk density of granules 0.175 0.120 0.150 0.100 0.114[g/mL] tapped density granules [g/mL] after  10 hubs 0.177 0.124 0.1560.103 0.118 1250 hubs 0.278 0.190 0.246 0.172 0.190 flowability granules− − − − − − − − − − − − − − − bulk density final 0.210 0.210 0.195 0.1900.185 mixture [g/mL] tapped density final mixture [g/mL] after  10 hubs0.217 0.217 0.203 0.200 0.197 1250 hubs 0.292 0.292 0.275 0.271 0.253flowability final mixture + − − + − − + − − + − − + − −

The granules and final compositions were evaluated in the manner setforth in Example 1 and the results are set forth in Table 4 above. Theformulations exhibited little to slight improvement in bulk density andpoor to insufficient flowability properties.

What is claimed is:
 1. A composition comprising granules comprising2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide, wherein the composition has a bulk density greater than 0.2g/mL.
 2. The composition of claim 1, wherein the composition furthercomprises5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diol.3. The composition of claim 2, wherein the ratio of the2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide to the5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diolranges from about 99:1 to about 95:5.
 4. The composition of claim 2,wherein the5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diolis present in an amount up to about 5% by weight, relative to the2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide.
 5. The composition of claim 2, wherein the5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diolis present in an amount up to about 3% by weight, relative to the2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide.
 6. The composition of claim 2, wherein the5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diolis present in an amount up to about 1% by weight, relative to the2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide.
 7. The composition of claim 2, further comprising at least oneadditional component chosen from fillers, diluents, binders,disintegrants, lubricants, and glidants.
 8. The composition of claim 2,wherein the bulk density of the composition is greater than 0.3 g/mL. 9.A pharmaceutical formulation comprising a composition comprisinggranules comprising2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide, wherein the composition has a bulk density greater than 0.2g/mL.
 10. The pharmaceutical formulation of claim 9, wherein thecomposition further comprises5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diol.11. The pharmaceutical formulation of claim 10, wherein the ratio of the2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide to the5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diolranges from about 99:1 to about 95:5.
 12. The pharmaceutical formulationof claim 10, wherein the5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diolis present in an amount up to about 5% by weight, relative to the2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide.
 13. The pharmaceutical formulation of claim 10, wherein the5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diolis present in an amount up to about 3% by weight, relative to the2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide.
 14. The pharmaceutical formulation of claim 10, wherein the5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diolis present in an amount up to about 1% by weight, relative to the2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide.
 15. The pharmaceutical formulation of claim 10, wherein theformulation is a dosage form chosen from tablets and capsules.
 16. Thepharmaceutical formulation of claim 10, wherein the formulation is atablet exhibiting an apparent density ranging from 0.5 g/mL to 1.5 g/mL.17. The pharmaceutical formulation of claim 10, wherein the total amountof the2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide and the5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diolis at least 10 mg.
 18. The pharmaceutical formulation of claim 10,wherein the total amount of the2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide and the5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diolis at least 20 mg.
 19. The pharmaceutical formulation of claim 10,wherein the total amount of the2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide and the5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diolis at least 40 mg.
 20. The pharmaceutical formulation of claim 10,wherein the total amount of the2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine1-oxide and the5-[3-(2,5-dichloro-4,6-dimethylpyridin-3-yl)-[1,2,4]oxadiazol-5-yl]-3-nitrobenzene-1,2-diolis at least 50 mg.